Progress in modelling of chemical-reaction limited wetting

In reactive metal/ceramic systems the wetting rate of small, millimeter sized droplets on smooth ceramic surfaces is controlled by the slower of two successive phenomena that intervene in the reaction process: diffusive transport of reacting species to or from the triple line, and local reaction kinetics at the triple line. The first case, of diffusive wetting, was modelled by Mortensen et al. [Scripta mater. 36 (1997) 645] a few years ago. The purpose of this paper is to present progress accomplished during the last few years in modelling the second type of wetting controlled by the reaction process at or close to the triple line. The predictions of equations derived from a model describing the change in contact angle and spreading rate with time are compared with experimental results obtained for different silicon alloys on carbon substrates.